RegExp.prototype.unicode
The unicode
accessor property indicates whether or not the u
flag is used with the regular expression.
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Description
RegExp.prototype.unicode
has the value true
if the u
flag was used; otherwise, false
. The u
flag enables various Unicode-related features. With the "u" flag:
- Any Unicode code point escapes (
\u{xxxx}
,\p{UnicodePropertyValue}
) will be interpreted as such instead of identity escapes. For example/\u{61}/u
matches"a"
, but/\u{61}/
(withoutu
flag) matches"u".repeat(61)
, where the\u
is equivalent to a singleu
. - Surrogate pairs will be interpreted as whole characters instead of two separate characters. For example,
/[😄]/u
would only match"😄"
but not"\ud83d"
. - When
lastIndex
is automatically advanced (such as when callingexec()
), unicode regexes advance by Unicode code points instead of UTF-16 code units.
There are other changes to the parsing behavior that prevent possible syntax mistakes (which are analogous to strict mode for regex syntax). This is explained in more detail in Using Unicode regular expressions.
The set accessor of unicode
is undefined
. You cannot change this property directly.
Examples
Using the unicode property
const regex = /\u{61}/u;
console.log(regex.unicode); // true
Specifications
Specification |
---|
ECMAScript Language Specification # sec-get-regexp.prototype.unicode |
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